1. Field of the Invention
The present invention relates to a power-assisted door closer for assisting in an opening or closing procedure of a door.
2. Related Art
Door closers known in the state-of-the-art include an output shaft which can be driven by a driving mechanism. The output shaft is, for example, connected to a door leaf by a scissor arm assembly or a sliding rail arm assembly. Furthermore, a closer spring acts upon the driving mechanism. By manually opening the door leaf, the output shaft is entrained into rotation. The closer spring is tensioned by the driving mechanism and thus stores the energy for the closing procedure. The closing procedure of the door leaf occurs without any manual intervention by the user. In this case, it is by means of the driving mechanism that the energy of the closer spring acts upon the output shaft and thus upon the door leaf. In particular in case of very heavy and large door leaves, assistance for tensioning the closer spring during the opening procedure and/or a dampening action of the door in the terminal position is required. For the door leaf to reliably latch into the latching mechanism, a sufficient closing moment is required in the area of the zero position of the door.